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June 2018 Update

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Ingy döt Net 2018-06-22 20:57:24 +00:00
parent ba8067c3b7
commit 22f33d4004
5278 changed files with 84726 additions and 14379 deletions
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20
Task/Bitcoin-address-validation/Java/bitcoin-address-validation.java
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@ -1,3 +1,4 @@
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
@ -9,7 +10,7 @@ public class BitcoinAddressValidator {
public static boolean validateBitcoinAddress(String addr) {
if (addr.length() < 26 || addr.length() > 35)
return false;
byte[] decoded = decodeBase58(addr, 25);
byte[] decoded = decodeBase58To25Bytes(addr);
if (decoded == null)
return false;
@ -19,22 +20,19 @@ public class BitcoinAddressValidator {
return Arrays.equals(Arrays.copyOfRange(hash2, 0, 4), Arrays.copyOfRange(decoded, 21, 25));
}
private static byte[] decodeBase58(String input, int len) {
byte[] output = new byte[len];
private static byte[] decodeBase58To25Bytes(String input) {
BigInteger num = BigInteger.ZERO;
for (char t : input.toCharArray()) {
int p = ALPHABET.indexOf(t);
if (p == -1)
return null;
for (int j = len - 1; j >= 0; j--) {
p += 58 * (output[j] & 0xFF);
output[j] = (byte) (p % 256);
p /= 256;
}
if (p != 0)
return null;
num = num.multiply(BigInteger.valueOf(58)).add(BigInteger.valueOf(p));
}
return output;
byte[] result = new byte[25];
byte[] numBytes = num.toByteArray();
System.arraycopy(numBytes, 0, result, result.length - numBytes.length, numBytes.length);
return result;
}
private static byte[] sha256(byte[] data) {